The present invention relates to a cooling structure and cooling method of a rotating electrical machine.
A structure described in Japanese Patent Application Publication No. JP-A-H9-182374 and a structure described in Japanese Patent Application Publication No. JP-A-2002-345188 have been proposed as a cooling structure of a rotating electrical machine.
Japanese Patent Application Publication No. JP-A-H9-182374 discloses an axial oil passage (32 in JP-A-H9-182374; the same below) that is provided, as a cooling circuit of a motor, radially inside of permanent magnets (31) and axially extends through a core (30); and a supply device (5) that supplies oil to the oil passage. In this example, as can be seen from FIG. 4 of JP-A-H9-182374, a part of a rotor core (rotor iron core) is interposed between the axial oil passage (32) and the permanent magnets (31), and the permanent magnets (31) are cooled indirectly (through the part of the rotor core) by a cooling liquid flowing through the axial oil passage (32).
Japanese Patent Application Publication No. JP-A-2002-345188 is an application relating to a rotating electrical machine, and this rotating electrical machine also includes a plurality of permanent magnets (12 in JP-A-2002-345188; the same below) at positions close to the outer periphery of a rotor. In this example, each magnet insertion hole (16) formed in a rotor core has a hole portion on its inner diameter side, and each hole portion has a triangular shape with an apex located on its inner diameter side. These hole portions serve as a cooling passage (15) through which cooling liquid flows. In this example, the cooling liquid flows in direct contact with the pole faces of the permanent magnets (12). Therefore, the permanent magnets (12) can be directly cooled.